It has already been proposed to use a water gun for directing a high-pressure spray onto a workpiece to be cleaned and to hold that workpiece during the cleaning operation on a temporary support, leaving it accessible from all sides except at its base. Attempts to design the support as a tiltable turntable, in order to avoid the need for lugging the water gun around, have run into problems of protecting the drive mechanism of that turntable from the detritus swept off the workpiece and entrained by the runoff. A similar problem arises when a recirculation system is used for the sake of water conservation as the entrained solids tend to interfere with the operation of the pumps.